1. Field of the Invention
This invention relates to an improved apparatus for cutting indicia on a multilayer tape, and in one aspect to an improved machine which reduces the forces necessary to effect the die cutting operation and suitably guides, supports, and advances a multilayer tape through the cutting station.
2. Description of the Prior Art
Cutting or creasing a web by forcing the same against a narrow raised surface on a plate is known in the art. An example of a die plate for cutting or creasing a web as described is illustrated in U.S. Pat. No. 2,782,851, issued Feb. 26, 1957, to M. E. Gazette. This cutting step illustrated in this patent is achieved by wrapping the die plate around a first roller and feeding the paper sheet to be cut between the die plate and an anvil roller. These rolls are rotated in opposite directions so that when the paper is introduced between the rollers the outline formed on the die plate cuts the paper sheet to form the separate pieces having a similar outline to that formed on the die plate. If creasing of the paper rather than cutting is desired the anvil roller is made from a material sufficiently yielding to prevent the wire from cutting through the paper.
A further system for cutting indicia from a web is illustrated in U.S. Pat. No. 3,673,953, issued Jul. 4, 1972, to B. J. Massari. In this patent there is illustrated the use of a die plate having an indicia formed in a raised rib thereon to cut indicia from a multilayer tape. In the machine the die plate is not wrapped about the surface of one of two opposed rollers but is positioned between the rollers at the nip thereof and is moved with the multilayer web through the nip area between a pair of rollers, one of which supports and guides the tape between the nip and the other forms the anvil roller. In this apparatus to acquire sufficient pressure the rollers must be rigidly mounted and uniformly driven to advance the die plate therebetween as the web is advanced. In this structure it was common to have to make a cut along a line defining an edge of the indicia as the same is moved through the nip. Thus, exact tolerances of the rollers is required to maintain the spacing and sufficient pressure therebetween along the length of the rollers.
Thus, to achieve uniformity and to maintain the pressure uniform during the cutting operation it is preferred that the roller move across the face of the cutting die in such a manner as to cut at spaced points along the die and not to cut along a line. This will reduce the tolerances and the size of the members necessary to accomplish the pressures which are required. Manufacturing tolerances will not be as precise in the equipment.
The type of tape which is adapted to be cut by this machine is disclosed in U.S. Pat. No. 3,558,425, issued Jan. 26, 1971 to B. J. Massari. This patent discloses a three-layer laminated stencil-forming tape having an upper carrier layer adapted to be embossed, an intermediate stencil layer to be cut during embossing of the upper layer, and a lower support layer which can be either cut or uncut during the embossing. The lower surfaces of both the upper carrier and the stencil-forming layer are provided with normally tacky and pressure-sensitive adhesive which not only serves to maintain the integrity of the laminate during processing but also assists in separating the cut indicia from the rest of the stencil layer and subsequently transferring them to a permanent supporting surface. An improved structure for the stencil-forming tapes is disclosed in United States application Ser. No. 591,106, filed June 25, 1975, by J. D. Laperre, and assigned to the assignee of this application and incorporated herein by reference. In this application the tape structure can be subjected to pressures of a cutting die without severing the upper carrier layer while still providing adequate definition of the character defined by the cutting die. The adhesion of the upper layer to the stencil layer significantly exceeds the adhesion of the stencil layer to the support layer thereby permitting the ready removal of the support layer after a sequence of indicia has been die cut from the stencil layer. Because the upper carrier layer maintains its integrity and is not severed, particularly in the direction at right angles to the edges of the tape, it can be employed to position the sequence of indicia in predetermined constant spaced position.